Re: [Sbcl-devel] Re: bogus arguments to MOV

[Cyrus H. <ch...@bo...>]

Hi Juho,

Turns out I was having another problem, which was causing this  
symptom to show up. I was trying to reference an alien variable in a  
library that recently switched to using the GCC 4 visibility stuff  
and had made a variable hidden. Unhiding the variable makes the  
problem go away. So I think this was a case of programmer error on my  
part. Your patch looks reasonable, but I know nothing about x86-64  
asm or how to generate anything to test it.

Thanks for the prompt response and my apologies for the half-baked  
problem report.

Cyrus

On Jan 6, 2006, at 7:06 PM, Juho Snellman wrote:

> <ch...@bo...> wrote:
>> I noticed there were some recent changes to the way we emit MOV
>> instructions on x86-64. I know nothing about x86-64, but I am seeing
>> an error:
>
> Probably just a coincidence. The problem has always existed (and has
> always been detected by the compiler at the same stage). Basically the
> float sap setters were bogus in situations where the return value was
> used, e.g.
>
> (defun foo (sap)
>   (let ((x (setf (sb-vm::sap-ref-double sap 0) 1d0)))
>     (1+ x)))
>
>> bogus arguments to MOV: #<SB-C:TN t1[FLOAT0]> <SB-C:TN t2[FLOAT1]> in
>> SB-VM::MOV-INST-EMITTER. I don't think I'm doing anything obviously
>> wrong (stale fasls, etc...).
>>
>> This is happening during a DEFINE-ALIEN-CALLBACK. Stack trace  
>> attached.
>>
>> Any suggestions?
>
> Does the following patch fix this for you?
>
> Index: src/compiler/x86-64/macros.lisp
> ===================================================================
> RCS file: /cvsroot/sbcl/sbcl/src/compiler/x86-64/macros.lisp,v
> retrieving revision 1.15
> diff -u -r1.15 macros.lisp
> --- src/compiler/x86-64/macros.lisp	15 Nov 2005 12:49:30 -0000	1.15
> +++ src/compiler/x86-64/macros.lisp	7 Jan 2006 02:50:16 -0000
> @@ -19,7 +19,13 @@
>    (once-only ((n-dst dst)
>                (n-src src))
>      `(unless (location= ,n-dst ,n-src)
> -       (inst mov ,n-dst ,n-src))))
> +       (sc-case ,n-dst
> +         (single-reg
> +          (inst movss ,n-dst ,n-src))
> +         (double-reg
> +          (inst movsd ,n-dst ,n-src))
> +         (t
> +          (inst mov ,n-dst ,n-src))))))
>
>  (defmacro make-ea-for-object-slot (ptr slot lowtag)
>    `(make-ea :qword :base ,ptr :disp (- (* ,slot n-word- 
> bytes) ,lowtag)))
>
> -- 
> Juho Snellman
>
>
>
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